user: Question: Name the number for viewers being 1.87
Columns: ['No.', '#', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (million)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [45.0, 1.0, '"Clone Cadets"', 'Dave Filoni', 'Cameron Litvack', 'September17,2010', '3.01', '2.42']
SQL:

assistant: SELECT "#" FROM "Table" WHERE "U.S. viewers (million)" = '1.87';