user: Question: Who was the democratic candidate when the republican was  Frank Wolf?
Columns: ['District', 'Incumbent', '2008 Status', 'Democratic', 'Republican', 'Independent Green', 'Libertarian', 'Other Party']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Rob Wittman', 'Re-election', 'Bill Day', 'Rob Wittman', 'None', 'Nathan Larson', 'None']
SQL:

assistant: SELECT "Democratic" FROM "Table" WHERE "Republican" = 'Frank Wolf';