Detroit 6-71 Crown oil change question.

[Rawlings]

Hey for any people that have experience with Detroit 6-71. I'm starting to buy all the fuel filters, oil filters, water conditioner filter. I cleaned the engine today as it was starting to get covered with oil and I noticed there's 2 fuel filters one says secondary on it and one is main I guess. I only see 1 oil filter it's big and connected directly to the oil pan / container. Is there just 1 oil filter, I thought there was two but I can't find any other, I went to the other side and all I see is just 1 small filter that says wix coolant filter conditioner. Anyone got any idea if it's just 1 filter I need for oil? Pictures attached below