user: Question: Who were the 3rd couple that were viewed by 4.89 million viewers? 
Columns: ['#', 'Airdate', 'No. of couples', '1st couple', '2nd couple', '3rd couple', '4th couple', 'Viewers (millions)', 'ITV1 weekly ranking']
Types: ['real', 'text', 'real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '11 December 2010', 3.0, 'Danny and Vicky', 'Adrian (n/a)', 'Alistair and Alisha', 'Iain and Fern', '5.96', '18']
SQL:

assistant: SELECT "3rd couple" FROM "Table" WHERE "Viewers (millions)" = '4.89';