user: Question: Who directed the episode that aired on July 29, 2011?
Columns: ['No.', '#', 'Title', 'Directed by', 'Written by', 'Canadian air date', 'U.S. air date', 'Production code', 'Canadian viewers (million)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [45.0, 1.0, '"Personal Effects" (Part 2)', 'Kelly Makin', 'Mark Ellis & Stephanie Morgenstern', 'July8,2011', 'July 8, 2011', 401.0, '1.369']
SQL:

assistant: SELECT "Directed by" FROM "Table" WHERE "U.S. air date" = 'July 29, 2011';