The Congress is leading over the BJP by a margin of over 10,000 votes in the first few hours of counting of votes for the Jayanagar assembly constituency.
While Congress candidate Sowmya Reddy was leading, BJP's B N Prahlad was in second position, poll officials said.
Fifty-five per cent polling was recorded in the Jayangar assembly constituency on June 11.
The assembly elections were held across the state on May 12, but poll in Jayanagar was countermanded following the death of BJP candidate B N Vijayakumar, who was holding the seat.
BJP's B N Prahlad, brother of Vijaykumar, and senior Congress leader and former minister Ramalinga Reddy's daughter Sowmya Reddy are locked in a direct contest for the seat.
In all, nineteen candidates are in the fray.