user: Question: when did the institution at Chapel Hill, North Carolina join acc?
Columns: ['Institution', 'Nickname', 'Location', 'Founded', 'Joined ACC', 'School Type', 'ACC Football Titles']
Types: ['text', 'text', 'text', 'real', 'real', 'text', 'real']
Sample row: ['Boston College', 'Eagles', 'Chestnut Hill, Massachusetts', 1863.0, 2005.0, 'Private/Jesuit', 0.0]
SQL:

assistant: SELECT "Joined ACC" FROM "Table" WHERE "Location" = 'Chapel Hill, North Carolina';