CREATE TABLE table_18330 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

What is the district that has Bob Wilson as an incumbent?
SELECT "District" FROM table_18330 WHERE "Incumbent" = 'Bob Wilson'
SELECT "District" FROM "table_18330" WHERE "Incumbent" = 'Bob Wilson'