user: Question: What district is Ray Musto the incumbent of?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Pennsylvania 6', 'Gus Yatron', 'Democratic', 1968.0, 'Re-elected', 'Gus Yatron (D) 67.1% George Hulshart (R) 32.9%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Ray Musto';