CREATE TABLE table_24430894_20 (year VARCHAR, mutya_ng_pilipinas_asia_pacific VARCHAR)

List the number of years where ritchie ocampo was the mutya ng pilipinas winner.
SELECT COUNT(year) FROM table_24430894_20 WHERE mutya_ng_pilipinas_asia_pacific = "Ritchie Ocampo"
SELECT COUNT("year") FROM "table_24430894_20" WHERE "Ritchie Ocampo" = "mutya_ng_pilipinas_asia_pacific"