user: Question: who was the successor for district Ohio 15th?
Columns: ['District', 'Vacator', 'Reason for change', 'Successor', 'Date successor seated']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Georgia 2nd', 'Vacant', 'Rep. Edward E. Cox died during previous congress', 'J. L. Pilcher (D)', 'February 4, 1953']
SQL:

assistant: SELECT "Successor" FROM "Table" WHERE "District" = 'Ohio 15th';