CREATE TABLE table_name_93 (opponent VARCHAR2, aces VARCHAR2, event VARCHAR2)

At the 2001 Davis Cup, what Opponent had less than 50 Aces?
SELECT opponent FROM table_name_93 WHERE aces < 50 AND event = "2001 davis cup"
SELECT "opponent" FROM "table_name_93" WHERE "2001 davis cup" = "event" AND "aces" < 50