The Congress on Friday re-nominated former union minister Vayalar Ravi as its candidate for biennial elections to the Rajya Sabha from Kerala."Congress president Sonia Gandhi has approved the candidature of Vayalar Ravi as Congress candidate to contest the ensuing biennial election to the Rajya Sabha from Kerala," a party release said.Ravi's term in the upper house is set to end on April 21. Two other Rajya Sabha members from the state - M.P. Achuthan of the Communist Party of India and P. Rajeeve of the Communist Party of India-Marxist - will also retire on the same day.The state is ruled by the Congress-headed United Democratic Front.