The BJP is trailing in two northern states it rules -- Himachal Pradesh and Haryana in the bypolls held on Saturday. The Congress is leading in Himachal, including the Mandi Lok Sabha seat. In Bengal, the ruling Trinamool Congress is ahead in all four seats. The bypolls in Dinhata and Santipur -- which the BJP held -- are seen as a prestige battle for the party, which is currently grappling with an exodus of MLAs and senior leaders after the Trinamool's sweeping victory in the April-May state polls.