Three (3) artists use the name "Duffy:"

1) 60's-sounding blues singer born in Bangor, Gwynedd, Wales, recently featured on Capital 95.8. Aimee Anne Duffy - known professionally as Duffy - released her debut single Rockferry in December 2007. After relocating to London in 2006, she came to the attention of Rough Trade. She is compared with late 60s soul diva Dusty Springfield and has experienced significant mainstream success with the single 'Mercy' reaching number one in the United Kingdom. The debut album was released in March 2008, and also made number one on the UK album chart. Bernard Butler of Suede worked extensively on the album therefore lending it an authentic and wonderfully produced lush 1960's sound.

2) Duffy is an American rock band stationed in Grand Rapids, MI. consisting of members Joe Girolamo (drums), Bill Kahler (piano), Eric Kehoe (guitar/vocals), and Joe Robert (bass). Their sound has been compared to 60's greats such as Neil Young, The Beatles, and The Kinks, and also to current bands such as Wilco and Ryan Adams Their first full length album, "Out of Doors," was released in 2007 on the Green Room Group label.

3) 'Duffy' was the alias used by British singer-songwriter Stephen Duffy during 1995-1998.

http://www.iamduffy.com