Mayer led by 16 points with 90 percent of the precincts reported late Tuesday night.
The 37th Senate District covers the cities of New Rochelle, Rye, White Plains, Yonkers and the towns of Bedford, Harrison, Mamaroneck, North Castle, Rye, Eastchester.
A Yonkers resident who represents the 90th district, Mayer won the nomination over West Harrison resident Mark Jaffe, teacher Kat Brezler, and Bedford Supervisor Chris Burdick. Yonkers Mayor Mike Spano dropped out before a nominee was chosen.
"Now, more than ever before, we need united and strong progressive leadership in Albany," Mayer said. "We cannot let the bigoted and hate-filled leadership in Washington take hold in Westchester. Democrats will continue to come together and rise up against those who try to use fear and hatred to undermine our unity."
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