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_15 (tournament VARCHAR, semi_finalists VARCHAR)
### Question:
Which Tournament has a Semi finalists of mary pierce elena dementieva?
### Answer:
SELECT tournament FROM table_name_15 WHERE semi_finalists = "mary pierce elena dementieva"