user: Question: How many directors are there for the episode that had 1.59 million U.S. viewers?
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: [34.0, 1.0, '"Hats and Bats"', 'Christopher Chulack', 'Jonathan Lisco', 'February13,2013', '3X7551', '1.16']
SQL:

assistant: SELECT COUNT("Directed by") FROM "Table" WHERE "U.S. viewers (million)" = '1.59';