Senior Congress leader from Odisha and IPL chairman Ranjib Biswal took oath as Rajya Sabha member in New Delhi today.The newly elected BJD MPs and former Odisha ministers Kalpataru Das and Sarojini Hembram had taken their oath as Rajya Sabha members yesterday.Three Biju Janata Dal leaders Kalpataru Das, Sarojini Hembram and AU Singh Deo and Congress leader Ranjib Biwal were elected to the Upper House recently.However, one of the four Rajya Sabha seats has fallen vacant after AU Singh Deo chose to contest the just concluded Assembly elections from Bolangir constituency in Odisha.