JD(U) nominee Sanjeev Kumar Singh was elected to the Legislative Council from the Kosi Teachers constituency.
Declaring the result for Kosi Teachers' constituency, Prabhat Kumar Gupta, additional chief electoral officer, said "Singh secured 7,766 votes and following the clearance of the Election Commission, he has been declared elected."
The JD (U) nominee was seeking re-election from the seat, which he had won in 2009 following the death of his father Sharda Prasad Singh.
The ruling JD(U) won the elections to Saran Graduate constituency, while its ally (BJP) emerged victorious from Gaya Graduate constituency.
Six-time MLC Mahachandra Singh, who recently switched over to ruling JD(U) from the Congress defeating his nearest Independent rival by around 2,200 votes.
Similarly, former state minister and BJP candidate Awadhesh Narayan Singh won the elections to Gaya Graduate constituency to register his entry to the upper house for the second consecutive term. He defeated his nearest Congress rival Ajay Kumar Singh by over 6000 votes
But the ruling party was in for a rude shock when its rebel candidate Sanjeev Shyam Singh trounced the six time legislator and Congress nominee Prof Arun Kumar in the Gaya Teachers' constituency.