user: Question: Which Poll source has an Arlen Specter* of ––, and a Tom Ridge* of 60%?
Columns: ['Poll source', 'Dates administered', 'Arlen Specter*', 'Pat Toomey', 'Tom Ridge*', 'Peg Luksik']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Suffolk', 'May 13, 2010', '––', '60%', '––', '9%']
SQL:

assistant: SELECT "Poll source" FROM "Table" WHERE "Arlen Specter*" = '––' AND "Tom Ridge*" = '60%';