What is duffys first song?

Duffy's debut song is "Mercy". It is a pop-oriented soul song written and produced by Duffy and Bernard Butler, and released on the album Rockferry (2008). The song reached number 1 in the UK Singles Chart, number 2 in Ireland, and number 14 in Australia. Despite her success, Duffy later retired from music, citing the difficulties of being in the public eye and the pressure to produce music quickly.