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_39 (social_ao VARCHAR, external_co VARCHAR, president VARCHAR)
### Question:
What Social AO has an External CO of elena buscher, and a President of harm van leeuwen?
### Answer:
SELECT social_ao FROM table_name_39 WHERE external_co = "elena buscher" AND president = "harm van leeuwen"