Since this is a modded PC drive, it used to be set to DS1 (pin12) and someone configured it to DS0 (pin10) so it now works as df0: natively, just look for the mod and reverse it.
Or you can just re-wire the cable.
If you don't want to rewire the cable nor can you locate the DSx mod to reverse it, you can always short pins 10-12 on the floppy and cut off the prong for pin 10.
This way SEL1 signals (pin12) will be routed to pin10 (SEL0 - which the drive listens to), yet with the cut-off prong the drive will be deaf to SEL0 signals on the cable.
