user: Question: What is the source of the move from Port Vale?
Columns: ['Name', 'Country', 'Type', 'Moving from', 'Transfer window', 'Ends', 'Transfer fee', 'Source']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Ankergren', 'DEN', 'Transfer', 'Brøndby', 'Summer', 2010.0, 'Undisclosed', 'Leeds United']
SQL:

assistant: SELECT "Source" FROM "Table" WHERE "Moving from" = 'Port Vale';