Remove first encountered elements from a second list Inspired by this question on Stackoverflow.

The task
Let's have two lists/arrays of integers: L1 and L2 of equal length. You need to identify in L2 the position of first occurrence of each number and remove from L1 the values on the corresponding positions. Then print/output the modified L1.
Any reasonable input/ouput format is accepted as long as the lists are distinguishable.
Example
L1 = [1 2 3 4 5 6 7 8 9]
L2 = [2 3 3 5 5 4 3 7 1]
First occurence of each number in L2:
L2 = [2 3 3 5 5 4 3 7 1]
      ^ ^   ^   ^   ^ ^
Corresponding elements to remove from L1:
L1 = [1 2 3 4 5 6 7 8 9]
      ^ ^   ^   ^   ^ ^
Output result:
[3 5 7]

Test cases
Input -- Output
[1,2,3,4,5,6,7,8,9];[2,3,3,5,5,4,3,7,1] -- [3,5,7]
[1,1,1];[1,2,3] -- []
[2,2,2];[1,1,1] -- [2,2]
[-1,0,2,123456];[-1,0,-1,0] -- [2,123456]
[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40];[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1] -- [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40]
APL(Dyalog Unicode), 8 6 bytes SBCS
/⍨∘~∘≠

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A function submission which takes L1 on the left and L2 on the right.
-2 bytes from Bubbler.
Explanation
/⍨∘~∘≠
/⍨     remove elements from L! identified by:
   ~   the bitwise negation of
     ≠ unique mask of L2