Duke served in the Louisiana state legislature, that's all. He did run for the US senate seat and for governor, but lost both even though he got more votes than the sitting republican governor in one race. Even though he was an early advocate of workfare and a big opponent of affirmative action, he has continued the increasingly ironic and disturbing pattern of white racists/racialists joining forces (at least ideologically) with muslim extremists. I think this is a case of cutting off your nose to spite your face, with Americans being the nose, and Jews the face.
He was neither. Duke was a one-term State representative in Louisiana. Despite his notorious baggage, he did not put forward any proposed legislation which was offensive. Of course, if memory serves, virtually everything that he *did* touch was voted down, regardless of the merit of the proposal. Republicans and Democrats alike sent him an immediate and continuous message that he was not welcome as a legislator.
Hey... maybe the source has the name wrong. Perhaps they're thinking of Senator Byrd.