user: Question: What is the average Joined with a Nickname of Wildcats in Longmeadow, Massachusetts?
Columns: ['Location', 'Nickname', 'Founded', 'Type', 'Enrollment', 'Joined', 'Left', 'Current Conference']
Types: ['text', 'text', 'real', 'text', 'real', 'real', 'real', 'text']
Sample row: ['Longmeadow, Massachusetts', 'Wildcats', 1897.0, 'Private', 1400.0, 1996.0, 2008.0, 'NECC']
SQL:

assistant: SELECT AVG("Joined") FROM "Table" WHERE "Nickname" = 'Wildcats' AND "Location" = 'Longmeadow, Massachusetts';