user: Question: Who was the winner on 15 December 1957?
Columns: ['Season', 'Date', 'Winner', 'Score [C ]', 'Venue', 'Competition round']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1951.0, '2 September 1951', 'Alianza Lima', '4–3', 'Stadium Nacional', 'Liga Prof. de Lima']
SQL:

assistant: SELECT "Winner" FROM "Table" WHERE "Date" = '15 December 1957';