user: Question: What is the name of the captain when teh shirt sponsor is N/A?
Columns: ['Team', 'Chairman', 'Head Coach', 'Captain', 'Kitmaker', 'Shirt sponsor']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Al Ahli', 'Abdullah Saeed Al Naboodah', 'Abdul Hamid Al Mistaki', 'Fabio Cannavaro', 'Adidas', 'Toshiba']
SQL:

assistant: SELECT "Captain" FROM "Table" WHERE "Shirt sponsor" = 'N/A';