That is a coolant hose coming from the heater core in the car if I recall, and it connects to a plastic hose junction on the block. It usually leaks (mine included) due to the rubber seal becoming hard and flat with the engine heat cycles.
Easy enough to replace with the vacuum pump off and then bleed or top the system off.........depending on how quick you are.
Get original from TPS if you have access or dealer.
I had to replace that hose also, due to the oil leak turning that hose to a very soft and sticky mess