Jharkhand Mukti Morcha (JMM) chief Shibu Soren filed his nomination papers from Dumka constituency in Jharkhand Monday.Shibu is the sitting MP from Dumka. His son and Chief Minister Hemant Soren, Finance Minister and Congress leader Rajendra Singh and Tourism Minister and RJD leader Suresh Paswan were present when Shibu filed his papers.Later, Shibu said: "I am seeking re-election to serve the people of my constituency."Hemant told reporters: "The UPA is united and Dumka seat is a prestige issue for the UPA. We appeal to people to ensure victory of Guruji (Shibu Soren)".Shibu has been elected six times from here. He faces a tough fight as the first chief minister and Jharkhand Vikas Morcha-Prajatantrik (JVM-P) president Babulal Marandi has thrown his hat into the poll ring from this constituency.Marandi, fighting on a BJP ticket, defeated Shibu in the 1998 and 1999 Lok Sabha elections.