user: Question: What are the categories of events that occurred after 2007 that were World Championships?
Columns: ['Competition', 'Venue', 'Year', 'Category', 'Result']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['World Championships', 'POL Leszno', 1999.0, 'World Class', 'Bronze']
SQL:

assistant: SELECT "Category" FROM "Table" WHERE "Year" > 2007.0 AND "Competition" = 'World Championships';