user: Question: how many times was the exposures 53?
Columns: ['Camera', 'Filter', 'Wavelength', 'Total exposure time', 'Exposures']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['WFPC2', 'F300W', '300nm (U-band)', '140,400s', 106.0]
SQL:

assistant: SELECT COUNT("Camera") FROM "Table" WHERE "Exposures" = 53.0;