user: Question: What is the length of the Laguna Seca Raceway circuit with a class of GTU?
Columns: ['Race', 'Length', 'Class', 'Circuit', 'Date']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['24 Hour Pepsi Challenge', '24 hours', 'All', 'Daytona International Speedway', 'January 30 January 31']
SQL:

assistant: SELECT "Length" FROM "Table" WHERE "Circuit" = 'Laguna Seca Raceway' AND "Class" = 'GTU';