That is the Engine oil LEVEL sensor, not the pressure sensor that operates your instrument panel oil PRESSURE gauge. The oil LEVEL sensor will operate a warning light if your oil LEVEL [quantity] drops too low in the pan. If your oil PRESSURE is actually dropping to 0 [zero] at a warm[or cold] idle you have other issues.

But, to answer your question, if you have oil leaking out of your oil level sensor connector, then you will need to replace the entire lever sensor and any related gaskets, or seals [o-rings].

I would recommend repairing your oil drain plug, and installing some 20/50 oil and a new oil filter, and see what that does for your oil PRESSURE before you replace a oil level sensor on a engine that may have serious internal issues.