user: Question: What extra has World Championships as the tournament, and 1st as the result?
Columns: ['Year', 'Tournament', 'Venue', 'Result', 'Extra']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1997.0, 'World Indoor Championships', 'Paris , France', '3rd', '4x400 m relay']
SQL:

assistant: SELECT "Extra" FROM "Table" WHERE "Tournament" = 'World Championships' AND "Result" = '1st';