This hose is a low pressure one. Your PD type engine only has high pressures inside the valve cover. There is a low-pressure lift pump in the tank, however, which might make a little spritz of a leak when you first remove the hose.
You can depressurize the 'low pressure' side of the system by opening the water separator on the bottom of the fuel filter (to the left of the frame of the photo you took; located at the other end of the hose in question). If for some reason this is inaccessible (some filters don't have it) you could just wrap a rag around the hose after you remove the clamp, and twist and pull to remove. The rag will be more than adequate to absorb any initial pressure release.
You're not in any grave danger. One look at the type of clamp on the hose should provide that much information. Keep the fuel system nice and clean, and when you go to start it the first time cycle the key switch a few times before going to crank it up. This will let the in-tank pump purge out any air you introduced.