"Load distinct ... " does work, but it compares the entire record, i.e. all fields. So if you still have "duplicates", then they differ in a field value. It could for example be an additional blank space or something similar.
An alternative, if you just want to filter out duplicates of an individual field you could try
Load TradeID, ... From ... Where not Exists(TradeID):
Then you will get only the first instance of each TradeID.