Zohran Mamdani declared victory in New York City’s Democratic mayoral primary Tuesday night after Andrew Cuomo conceded the race in a stunning upset, as the young, progressive upstart who was virtually unknown when the contest began built a substantial lead over the more experienced but scandal-scarred former governor.

Zohran Mamdani, a state assemblyman and democratic socialist, had a commanding lead over former Gov. Andrew M. Cuomo, who conceded in the Democratic primary.

Andrew Cuomo called state Assemblyman Zohran Mamdani to congratulate him Tuesday night, saying he won the New York City Democratic mayoral primary election.With 91% of the vote in, Mamdani had 43.5% and Cuomo had 36.