Duffy swung over a corner that Leicester keeper Kasper Schmeichel fumbled into his own net under no pressure whatsoever.
The goal has initially been penned down as a Schmeichel own goal but replays suggest that the ball was curling towards goal, so it could be awarded to Duffy.
"I'm trying to claim it," he told Rovers' official website. "A few of the lads are trying to take it off me but I've just put it in an area and [Schmeichel's] come out and mishandled it and it's gone in the net. Like I said, I'm gonna claim it."
Three points saw Donny move six clear of the Championship drop zone and up to 16th in the table.