Challenger Rachel May has upended incumbent State Sen. David Valesky in the 53rd State Senate District's Democratic primary election.

With all precincts reporting, May had a 8,013-7,407 vote advantage over Valesky on Thursday night. Valesky, however, said he will not concede until all absentee ballots are counted.

Onondaga County Board of Elections Commissioner Dustin Czarny says there are 890 absentee ballots that need to be counted which includes parts of Onondaga and Oneida counties as well as all of Madison County.  

He expects more absentees will continue to come in over the next week. 

"As they come in from out of state or ones that we're mailed in late or ones that we're dropped off at the polling places. So, we'll know more numbers next week. Most of the boards are going to be opening up absentee ballots next Thursday so we'll have a final result then," he told Spectrum News.

Valesky's apparent defeat was one of a number of setbacks for Democratic state senators who were once in the Independent Democratic Conference, a group of eight Democratic senators who caucused independently and occasionally aligned with Republicans. Five of six ex-IDC state senators in New York City also lost their primary elections Thursday.

Valesky could still challenge May this November on the Women's Equality and Independence lines, but told Spectrum News that he'll make his decision once the Democratic primary race is officially settled.