He had been with Dundee and Forfar Athletic as a youth before joining Clyde from junior club Camelon and also had a spell in English football with HartlepoolUnited.
He joined Huddersfield last year but was most recently loaned out to League One rivals HartlepoolUnited after having been kept out the side by Dundee United target Danny Cadamarteri.
Former Rangers and Scotland Under-21 player Duffy had also been linked with a move to Scottish Premier League sides Hearts and Hibernian, while HartlepoolUnited were also thought to be keen.
In London, Ken Livingston defeated Labour's own Frank Dobson to become mayor, while in Hartlepool, Stuart Drummond, - aka HartlepoolUnited FC mascot H'Angus the Monkey - became mayor on a ticket of free bananas for schoolchildren.
Pardew is the fourth Football League manager to leave his club this season, after Steve Coppell at Bristol City, Kevin Blackwell at Sheffield United and Chris Turner at Hartlepool.