user: Question: Who was the away team when the home team scored 20.15 (135)?
Columns: ['Home team', 'Home team score', 'Away team', 'Away team score', 'Venue', 'Crowd', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Essendon', '13.11 (89)', 'Melbourne', '12.7 (79)', 'Windy Hill', 15000.0, '30 August 1930']
SQL:

assistant: SELECT "Away team score" FROM "Table" WHERE "Home team score" = '20.15 (135)';