user: Question: How many incumbents come from Alvin Bush's district?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Pennsylvania 6', 'Hugh Scott', 'Republican', 1946.0, 'Retired to run for U. S. Senate Democratic gain', 'Herman Toll (D) 55.4% Fred C. Gartner (R) 44.6%']
SQL:

assistant: SELECT COUNT("Candidates") FROM "Table" WHERE "Incumbent" = 'Alvin Bush';