user: Question: What's the total number of directors who've directed episodes seen by 11.34 million US viewers?
Columns: ['Series #', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '"Pilot"', 'Simon West', 'Jim Leonard', 'October4,2005', '475234', '10.43']
SQL:

assistant: SELECT COUNT("Directed by") FROM "Table" WHERE "U.S. viewers (millions)" = '11.34';