user: Question: What were the official itv ratings in millions for the episode with a total of 8.53 million itv viewers
Columns: ['Episode', 'Date', 'Official ITV rating (millions)', 'Weekly rank', 'Share (%)', 'Official ITV HD rating (millions)', 'Total ITV viewers (millions)']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'text']
Sample row: ['Auditions 1', '13 April', '9.58', 1.0, '36.9', '1.15', '10.73']
SQL:

assistant: SELECT "Official ITV rating (millions)" FROM "Table" WHERE "Total ITV viewers (millions)" = '8.53';