user: Question: What is the general classification with a 13 stage?
Columns: ['Stage', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Christian Vande Velde', 'no award', 'no award', 'Chris Anker Sørensen']
SQL:

assistant: SELECT "General classification" FROM "Table" WHERE "Stage" = '13';