OBC leader and BJP candidate Alpesh Thakor on Thursday lost the byelection to Radhanpur Assembly seat in Gujarat.
Congress' Raghubhai Desai defeated Thakor by over 3,500 votes, an official said.
Thakor, who emerged as an OBC leader during the Patel quota agitation and won the Radhanpur seat in the 2017 polls on Congress' ticket, later quit after differences with the state party leadership.
The by-election to the seat became necessary after he resigned as an MLA.
He earlier opposed the inclusion of Patidar community in the Other Backward Class (OBC) category for reservation.
His close aide Dhavalsinh Jhala, who also switched over to the BJP, also lost the by-election from Bayad Assembly seat.