Hello Hatem,
The replication of LOBs, BLOBs and CLOBs from Oracle to MySql is not currently supported (or for any non-Oracle targets):
https://dbvisit.atlassian.net/wiki/display/ugdr/Supported+and+Unsupported+Datatypes
Therefore what you will need to do is to exclude the column(s) in question from the replication. For more detail on this please see HERE.
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