user: Question: What construction completed is named Nelson Tunnel/Commodore Waste Rock?
Columns: ['CERCLIS ID', 'Name', 'County', 'Proposed', 'Listed', 'Construction completed', 'Partially deleted']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['CO7570090038', 'Air Force Plant PJKS', 'Jefferson', '07/14/1989', '11/21/1989', '–', '–']
SQL:

assistant: SELECT "Construction completed" FROM "Table" WHERE "Name" = 'Nelson Tunnel/Commodore Waste Rock';