CREATE TABLE table_name_3 (incumbent VARCHAR, district VARCHAR)
SELECT incumbent FROM table_name_3 WHERE district = "ohio 13"
ใครคือผู้ดำรงตำแหน่งที่มีเขตโอไฮโอ 13 ในพรรคเดโมแครต?
Who is the Incumbent that has a District of ohio 13 in Democratic Party?