Hyderabad: Several senior leaders of Congress are thronging by-election-bound Huzurabad assembly constituency to campaign for their party candidate Balmuri Venkat Narsing Rao. Ahead of the by-poll, Congress received a shock when its Huzurabad constituency in-charge Padi Koushik Reddy switched his loyalties to ruling Telangana Rashtra Samithi. BJP candidate Etala Rajendar and TRS nominee Gellu Srinivas Yadav, backed by their respective …