This is done with the LIMIT and OFFSET keywords. LIMIT is how many rows to return. OFFSET is the first row of your result set.
Keep in mind that a database stores sets of data -- unless you specify how to order your data, there is no guarantee that the same query will return the result set in the same order. It's always a good idea to use SOME sort of explicit ordering (using ORDER BY <column>) when using LIMIT and OFFSET clauses in your query.