user: Question: What was the description when the viewers selected Nan?
Columns: ['Task No.', 'Day announced', 'Description', 'Options', 'Viewers selection', 'Result']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [3.0, 'Day 45 (May 6, 2008)', 'Shy must drive which male housemate mad?', 'Ejay, Alex, Nan', 'Nan', 'Completed']
SQL:

assistant: SELECT "Description" FROM "Table" WHERE "Viewers selection" = 'Nan';