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_37 (match INTEGER, ground VARCHAR, opponent VARCHAR)
### Question:
What match number has a ground of H and the opponent Chelsea under 18s?
### Answer:
SELECT AVG(match) FROM table_name_37 WHERE ground = "h" AND opponent = "chelsea under 18s"