There is no direct Access equivalent for this particular function. Also, the vast majority of the users here will not know PL\SQL so you would do well to explain what that SQL actually does, ideally in natural English.
In Oracle, Informix (my own database home) and other enterprise-scale databases, a primary key can be an autonumber, same as in MSAccess. However, this is simply a sequential number guaranteed to be unique. It is a gapped series, because records can be deleted. A concept such as rowid is, as I understand it, actually a mapping device, indicating the record which is currently the record which is that number of records removed from the head of the table. It is, so far as I know, used only to identify the current record of interest and to ensure that any operations (update, etc.) are carried out only on that record. I do not believe that the concept exists in Access, though I daresay, one could open a recordset and physically count one's way down to the record of interest. Not good for performance, though !
If you are intending to do a cleanup of duplicates, the following technique might work.
Add an autonumber field (RecordId, say). Then create a query (or even a temporary table) populated by selecting Min(RecordId) As RealId, field1, field2, field3 grouping by field1, field2, field3. Then do an inner join between the query and the original table and delete all records where the field1s, field2s and field3s match but RealId is not equal to RecordId.