user: Question: How many different people directed the episode titled "Born Under a Bad Sign"?
Columns: ['No. in series', 'No. in season', '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: [23.0, 1.0, '"In My Time of Dying"', 'Kim Manners', 'Eric Kripke', 'September28,2006', '3T5501', '3.93']
SQL:

assistant: SELECT COUNT("Directed by") FROM "Table" WHERE "Title" = '"Born Under a Bad Sign"';