Thanks to Larry, a current Ringling clown, for the information:
The Gag with the fake leg is the clown is actually standing in and
walking in the box but with the fake legs it makes it look like the
duck is pulling him!
His name is Paul Winchell
he was a genius at creating unique props! (all made to pack flat and play big!)
But for you might remember him as the voice of Gargamel in the Smurfs.
Aug. 2, 1949
Ringling Circus Clown with Duck
Clown with harnessed Duck. | Circus
Chicago, Illinois, United States (Cook county)
Ringling Brothers Barnum and Bailey Combined Shows