Not enough information. What wire goes to what pot terminal depends on how the OTHER end of the cable is connected.
If I was wiring the whole system, I would wire it as follows, just out of habit:
Red---Positive voltage Black ---Negative voltage (or ground) White---Pot wiper (to drive speed input signal)
Typically, the Positive supply voltage goes to the CW terminal of the pot. This way, CW rotation produces a positive output voltage, and increasing speed. But this is subject to the specifics of your installation.
If this is a speed control pot for use with a VFD or something like that, typically it is set up as a variable voltage divider across a DC reference supply, to provide a 0-5V, 0-10V, +/-5V, or +/-10V speed command signal. You should ground the shield only at the drive end, and leave it float at the pot end.
5 ohms is a very low value for a speed control pot. Are you sure you don't mean 5 kilohms (5,000 ohms)?