Hi Aryun: Those files are not duplicates. Files are recorded in a series and each new recording (anything over the limit to the data storage, which in HD is around 13 minutes of video)has a new but consecutive number added to the end. This is how your NLE knows the order of a bunch of clips you import.
So "613_0318_01.MP4" is the first file in the 613_0318 series and the next one is "613_0318_02.MP4". This structure can also help you locate or identify files.
In terms of Log and Transfer, I don't use it because I use XDCAM EX 50i files in Quicktime rather than .mp4. I import the clips into a folder on the hard drive then import those clips to my FCP 7 project without using Log and Transfer. You have to use Log and Transfer to 'decode' the codec in the .mp4 clips because FCP 7 cannot natively edit .mp4 files.
As I remember the process, in FCP 7, open log and transfer, navigate to your memory card, select the folder immediately after the first and second folder. In my case, that is: Card 1/Private/the one with the akronym which contains the video files. On my JVC camera which records in HD and SD, there are two folders; one for HD and one for SD. So I select the correct folder and the clips import and convert to quicktime right away.