user: Question: Who wrote episode number 18?
Columns: ['№', '#', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [123.0, 1.0, '" Lessons "', 'David Solomon', 'Joss Whedon', 'September24,2002', '7ABB01', '5.00']
SQL:

assistant: SELECT "Written by" FROM "Table" WHERE "#" = 18.0;