For exporting the DDL of data objects without the storage specifications, this is what we should do:
EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'STORAGE',false);
select DBMS_METADATA.GET_DDL('TABLE','PROJECTS') from DUAL;
EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'DEFAULT');