I will take a pop shot at the question.....
I would run a python script that removes duplicate lines before you need to use the CVS .... Then your model would not have to worry about duplicate values. In the example below, 1.csv contains duplicate lines; the script create a 2.csv that removes the duplicates. You would use 2.csv in your model.
inFile = open('1.csv','r')
outFile = open('2.csv','w')
listLines = []
for line in inFile:
if line in listLines:
continue
else:
outFile.write(line)
listLines.append(line)
outFile.close()
inFile.close()
