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_83 (years VARCHAR, nationality VARCHAR, position VARCHAR)
### Question:
What is Years, when Nationality is United States, and when Position is PG / SG?
### Answer:
SELECT years FROM table_name_83 WHERE nationality = "united states" AND position = "pg / sg"