user: Question: Which series had a release on 1939-07-15 with the 8863 production number?
Columns: ['Title', 'Series', 'Director', 'Production Num.', 'Release date']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['The Lone Stranger and Porky', 'LT', 'Bob Clampett', '8743', '1939-01-07']
SQL:

assistant: SELECT "Series" FROM "Table" WHERE "Release date" = '1939-07-15' AND "Production Num." = '8863';