user: Question: What is the earliest year a house opened?
Columns: ['House name', 'House mascot', 'House colour', 'Year opened', 'House leader']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Hillary', 'Yeti', 'Green', 1980.0, 'Mrs Wong']
SQL:

assistant: SELECT MIN("Year opened") FROM "Table";