user: Question:  what's the date of completion where success is Yes
Columns: ['Symbol', 'Description', 'Success', 'Date of completion', 'Deadline for completion']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['NEWIPOD', 'Apple releases wide-aspect ratio touch screen iPod', 'Yes', 'September 5, 2007', 'September 30, 2007']
SQL:

assistant: SELECT "Date of completion" FROM "Table" WHERE "Success" = 'Yes';