Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_93 (category VARCHAR, year VARCHAR, competition VARCHAR)
### Question:
What are the categories of events that occurred after 2007 that were World Championships?
### Answer:
SELECT category FROM table_name_93 WHERE year > 2007 AND competition = "world championships"