user: Question: What year did a team from North Dearborn leave?
Columns: ['School', 'City', 'Team Name', 'County', 'Year Joined', 'Year Left']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Aurora', 'Aurora', 'Red Devils', '15 Dearborn', '1956', '1978']
SQL:

assistant: SELECT "Year Left" FROM "Table" WHERE "School" = 'North Dearborn';