As of early Wednesday morning, the battle between Republican incumbent Donna Simon and Democratic challenger Andrew Zwicker in central Jersey's 16th District remained too close to call — with only 29 votes separating them
TRENTON -- It might be a while before New Jersey knows the winner of this year's tightest state Assembly race.
As of early Wednesday morning, Democratic challenger Andrew Zwicker the battle between Republican incumbent Donna Simon in central Jersey's 16th District remained too close to call -- with Zwicker leading the unofficial tally by only 29 votes.
Provisional ballots are still being counted, and that is likely to take through Friday because the district includes parts of four counties -- Hunterdon, Mercer, Middlesex, and Somerset -- which are each tallying votes, said Mark Matzen, an adviser to Zwicker.
The losing candidate would then have until Wednesday, Nov. 18, to file for a recount, Matzen said.
MORE: Democrats win their largest N.J. Assembly majority in 36 years
"We're not done yet," Assembly Minority Leader Jon Bramnick (R-Union), the top Republican in the chamber, said Wednesday.
The state Division of Elections did not immediately return a message seeking comment Wednesday.
The winner will determine whether Democrats will score an even greater victory in Tuesday's elections than originally expected. Democrats tightened their control on the Assembly -- the lower house of the state Legislature -- by picking up three seats. That would bring their total to 51 seats in the 80-member lower house in January, their biggest majority since 1979.
If Zwicker -- a Princeton University physicist who ran an unsuccessful bid for Congress last year -- wins, that would be a gain of four seats.
MORE: Complete election results from across N.J.
The Associated Press originally declared that Simon -- an Assemblywoman since 2012 -- and her running mate, Republican Assemblyman Jack Ciatarelli, had won re-election for the district's two seats late Tuesday night. And Zwicker had already delivered his concession speech.
But just after midnight, the AP said the margin was too thin to declare.
"It was kind of strange and surreal," Matzen said. "But that's what elections kind of are sometimes."
The closeness of the race surprised many pundits, who had not predicted the race to be one of the ones to watch Tuesday.
"This was absolutely a surprise," said Patrick Murray, director of the Monmouth University Polling Institute.
So what happened? Ben Dworkin, a political science professor at Rider University, said the district has traditionally been Republican, but it has Democratic towns -- like Princeton and South Brunswick.
And Tuesday's races were expected to draw a record-low turnout.
"If there was a much larger turnout, it might not be as close," Dworkin said.
He added that Zwicker's campaign also obtained a huge amount of information about individual voters.
"Zwicker worked his butt off," Murray said.
Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.