user: ### NOW ANSWER:
Question: What year did the team from City of Aurora join?
Columns: ['School', 'City', 'Team Name', 'Enrollment 08-09', 'IHSAA Class', 'IHSAA Class Football', 'County', 'Year Joined (Or Joining)', 'Previous Conference']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Batesville', 'Batesville', 'Bulldogs', 677.0, 'AAA', 'AAA', '69 Ripley', 1956.0, 'Southeastern Indiana']
SQL:

assistant: SELECT AVG("Year Joined (Or Joining)") FROM "Table" WHERE "City" = 'Aurora';