The trends made available by the Election Commission at 10:30 AM show the secular alliance parties leading in 7 seats with the RJD and JD(U) leading in three each and Congress in 1 seat.
BJP is leading in Narkatiaganj, Banka and Mohania (SC) seats, the EC statement said.
RJD of Lalu Prasad is ahead at Rajnagar (SC), Chapra and Mohiuddinagar.
Ruling JD(U) of Nitish Kumar is leading at Jale, Hajipur and Parbatta.
Congress is ahead at Bhagalpur.
In the 2010 Assembly election, BJP had won 6, RJD 3 and JD(U) 1 seat respectively.
The regrouped "Mandal forces" appears to have checked division of votes which is a setback for BJP which had won 31 seats out of 40 in Bihar in the recent general election with ally LJP and RLSP.