user: Question: What is the highest number of viewers for the episode that has an 18-49 of 1.8/6?
Columns: ['Episode', 'Air Date', 'Timeslot', '18-49', 'Viewers']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Gary Has a Dream', 'September 23, 2009', 'Wednesday 8:30 pm', '2.4/7', 7.37]
SQL:

assistant: SELECT MAX("Viewers") FROM "Table" WHERE "18-49" = '1.8/6';