Democratic Assemblyman Elihu Harris of Oakland has filed papers declaring his intention to run for mayor of Oakland. The six-term Oakland legislator filed statements in Oakland and Sacramento last week that he had established a campaign fund-raising committee for the 1990 race, in which he may end up challenging his longtime friend Mayor Lionel Wilson. Harris, 41, had said previously he would not run if Wilson decided to run for a fourth term. But Harris’ chief of staff, Jon Waldie, said Wednesday that Harris will run regardless of the 74-year-old mayor’s decision. Wilson has said he will announce his decision late this month. City councilman Leo Bazile filed fund-raising papers last month.