CREATE TABLE table_18393 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" TEXT, "Result" TEXT, "Candidates" TEXT)

Who's the incumbent of Indiana 4 district?
SELECT "Incumbent" FROM table_18393 WHERE "District" = 'Indiana 4'
SELECT "Incumbent" FROM "table_18393" WHERE "District" = 'Indiana 4'