user: Question: Which competition features the 1st round of Club Union Luxembourg?
Columns: ['Season', 'Competition', 'Round', 'Club', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1967/1968', 'Inter-Cities Fairs Cup', '1st round', 'Rangers F.C.', '1:1, 1:2']
SQL:

assistant: SELECT "Competition" FROM "Table" WHERE "Round" = '1st round' AND "Club" = 'Union Luxembourg';