What to use to repair puncture in siding

[challenders]

We just bought a used (obviously ) 1982 Sunline Travel Trailer..While walking around and really inspecting the siding yesterday, I realized there is a small puncture in the front, about a 1 1/2 ft down from the window. It's about an inch, but I had to really look to realize what it was... This is exactly where we've found water damage inside the trailer..We're hoping we've found the source of the leak...

My husband and I aren't sure what is the best way to handle fixing this.. Should we use a bondo type product or a caulk product like Dicor Self Leveling Sealant?

I'm going to be painting the trailer after we get done with all the repairs so this spot will have another layer on top of what ever we repair it with...