user: Question: What is the US air date when the director is Ken Girotti?
Columns: ['Series #', 'Title', 'Directed by', 'Written by', 'France air date', 'Canadian air date', 'US air date']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '"Pilot" "Pilote"', 'John Stead & Duane Clark', 'Gil Grant', '18April2011', '19 April 2011', '29 June 2012']
SQL:

assistant: SELECT "US air date" FROM "Table" WHERE "Directed by" = 'Ken Girotti';