CREATE TABLE table_1341707_15 (incumbent VARCHAR, district VARCHAR, party VARCHAR, result VARCHAR)

Who was the democratic incumbent in the Illinois 11 district who was re-elected?
SELECT incumbent FROM table_1341707_15 WHERE party = "Democratic" AND result = "Re-elected" AND district = "Illinois 11"
SELECT "incumbent" FROM "table_1341707_15" WHERE "Democratic" = "party" AND "Illinois 11" = "district" AND "Re-elected" = "result"