user: Question: Which network has a play-by-play announcer of John Wells?
Columns: ['Year', 'Network', 'Play-by-play', 'Colour commentator(s)', 'Studio host']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1989.0, 'CBC', 'Bob Cole', 'Harry Neale and Dick Irvin, Jr.', 'Ron MacLean']
SQL:

assistant: SELECT "Network" FROM "Table" WHERE "Play-by-play" = 'John Wells';