CREATE TABLE table_18170 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

Who's the incumbent of district Wisconsin 5?
SELECT "Incumbent" FROM table_18170 WHERE "District" = 'Wisconsin 5'
SELECT "Incumbent" FROM "table_18170" WHERE "District" = 'Wisconsin 5'