Hi Kelvin,
how about you check the documentation first?
LOB datatypes are explained in the documentation.
In order to get from Oracle to SAP HANA, one of the most convenient options is to use SAP DataServices.
LOB compression/de-duplication is currently not available (and honestly it's not the most prominent feature on any DBMS as it stems back to the days of database-as-a-filesystem approaches).
- Lars