Ranjib Biswal took oath as a Rajya Sabha Congress member in New Delhi on Wednesday.The BJD’s Kalpataru Das and Sarojini Hembram had taken their oaths as RS members on Tuesday. Three BJD leaders Das, Hembram and AU Singh Deo and the Congress’ Ranjib Biwal were elected to the Rajya Sabha recently. However, one of the RS seats has fallen vacant after Singh Deo contested the Assembly elections.