What was the surface for Adrian Ungur as an opponent?
CREATE TABLE table_name_86 (
    surface VARCHAR,
    opponent VARCHAR
)
SELECT surface FROM table_name_86 WHERE opponent = "adrian ungur"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What was the surface for Adrian Ungur as an opponent? ### Input: CREATE TABLE table_name_86 (
    surface VARCHAR,
    opponent VARCHAR
) ### Response: SELECT surface FROM table_name_86 WHERE opponent = "adrian ungur"