user: Question: Name the number of district for Tom Marino
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Pennsylvania 1', 'Bob Brady', 'Democratic', 1998.0, 'Re-elected', 'Bob Brady (D) 85.1% John Featherman (R) 15.0%']
SQL:

assistant: SELECT COUNT("District") FROM "Table" WHERE "Incumbent" = 'Tom Marino';