Only two states in the nation, Louisiana and Mississippi, have never elected an openly L.G.B.T.Q. lawmaker. Now, there will be only one. On Tuesday, Fabian Nelson won a Democratic primary runoff in Mississippi’s 66th state House district, southwest of Jackson, where Republicans have no candidate on the ballot. Mr. Nelson, 38, was raised in the Mississippi Delta by politically active parents. And while he said he believed having a gay man in the State Legislature was significant, the historic nature of his campaign was never his focus. When he campaigned in South Jackson, he talked about the city’s water crisis and about crime. When he campaigned in rural areas, he talked about broadband access and economic development.