Abhay Singh Chautala of the Indian National Lok Dal (INLD) on Tuesday won the by-election of Ellenabad in BJP-JJP ruled Haryana with a margin of 6,708 votes.
He defeated Govind Kanda of the BJP. Congress nominee Pawan Beniwal finished third and lost his deposits.
The bypoll was necessitated with Chautala's resignation as the legislator in January in protest against three central farm laws.
After winning the bypoll in 2010, Chautala retained the seat in 2014 and 2019.
BJP's Gobind, brother of Haryana Lokhit Party chief and legislator Gopal Kanda, had joined the party just before the bypoll.
Beniwal, who had unsuccessfully contested the previous Assembly poll against Chautala, switched to the Congress from the BJP too, ahead of the bypoll.