user: Question: What opera has 19.87% as the firefox?
Columns: ['Period', 'Internet Explorer', 'Firefox', 'Chrome', 'Safari', 'Opera', 'Other']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['2013 Q1', '55.58%', '20.09%', '16.76%', '5.32%', '1.77%', '0.48%']
SQL:

assistant: SELECT "Opera" FROM "Table" WHERE "Firefox" = '19.87%';