user: Question: Who won stage 18?
Columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification', 'Team classification', 'Combativity award']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Fabian Cancellara', 'Fabian Cancellara', 'Fabian Cancellara', 'Alberto Contador', 'Roman Kreuziger', 'Astana', 'no award']
SQL:

assistant: SELECT "Winner" FROM "Table" WHERE "Stage" = 18.0;