user: Question: where is the district where the incumbent is Del Latta?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Ohio 2', 'Bill Gradison', 'Republican', 1974.0, 'Re-elected', 'Bill Gradison (R) 68.6% Thomas J. Porter (D) 31.4%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Del Latta';