Answer
Cesar Cielo has held the world record in the 50-metre freestyle (long course) for over 10 years. He set the record in 2009 with a time of 20.91 seconds, which was later broken by Florent Manaudou in 2014. However, Cielo regained the record in 2015 with a time of 20.90 seconds, and he has held it ever since.