The Leg Hose is attached into the Leg Hose Connector and is located on the left thigh of the Ghostbusters 1 uniform, the Khaki uniform used in Ghostbusters 2, and the khaki Video Game Uniform. It is not clear if it was meant to attach some where onto the back of the belt but is stuffed behind the belt.
There are fan made options such as fobs or tarp clips to mount to the belt to hold the other end of the hose. These are not accurate options, but they are functional.
Ghostbusters 2 Screen grab showing the clear hose on the khaki uniform:
Ghostbusters 2 screen grab showing there is not a clear hose or leg hose connector on the charcoal uniform.