user: Question: What club received a DF player for Free?
Columns: ['Exit Date', 'Pos.', 'Player', 'To club', 'Transfer fee']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2 July 2008', 'GK', 'Andreas Isaksson', 'PSV Eindhoven', 'Undisc.']
SQL:

assistant: SELECT "To club" FROM "Table" WHERE "Transfer fee" = 'Free' AND "Pos." = 'DF';