human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Year, Championship, Partner, Opponents in the final, Score
###Question: which opponents in the u.s. championships played after 1945 and had a score of 3–6, 6–4, 2–6, 6–3, 20–18?
gpt
SELECT Opponents in the final FROM table WHERE Championship = u.s. championships AND Year > 1945 AND Score = 3–6, 6–4, 2–6, 6–3, 20–18