Which one?
The big tube is the oil return line that's gravity fed more or less and it just pushes into a rubber grommet in the block. May weep a bit of oil at the block but there is not much of a fix as the grommet isn't much of a seal but any weeping at that point is harmless.
The skinny tube is the oil feed line. At the block end there is a fitting plug that threads into a port in the upper oil gallery, could be leaking around the threads of the fitting plug if it's a shade loose (there is a copper crush washer there), and something like a ball/socket joint at the end of the feed line that fits into the fitting and is held in place by a "nut" on the feed line (see the part picture at idParts), could be that nut is a bit loose. The next to last pic at
viewtopic.php?f=98&t=74594 shows the fitting. To get in there you like have to remove the heat shroud and maybe the vacuum tower behind the air filter.
There is no oil sensor in there.