user: Question: Name the team classification for stage of 20
Columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification', 'Team classification', 'Combativity award']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Fabian Cancellara', 'Fabian Cancellara', 'Fabian Cancellara', 'Alberto Contador', 'Roman Kreuziger', 'Astana', 'no award']
SQL:

assistant: SELECT "Team classification" FROM "Table" WHERE "Stage" = '20';