user: Question: What is the number of the truck that has the crew chief Billy Wilburn?
Columns: ['Team', 'Truck(s)', '#', 'Driver(s)', 'Primary Sponsor(s)', 'Listed Owner(s)', 'Crew Chief']
Types: ['text', 'text', 'real', 'text', 'text', 'text', 'text']
Sample row: ['Billy Ballew Motorsports', 'Toyota Tundra', 15.0, 'Shane Sieg', 'Phoenix Construction', 'Billy Ballew', 'Richie Wauters']
SQL:

assistant: SELECT "#" FROM "Table" WHERE "Crew Chief" = 'Billy Wilburn';