CREATE TABLE table_21060 ("Name" TEXT, "Latitude" TEXT, "Longitude" TEXT, "Diameter" TEXT, "Year named" FLOAT, "Namesake" TEXT)

What is the namesake of the feature found at 189.5w longitude?
SELECT "Namesake" FROM table_21060 WHERE "Longitude" = '189.5W'
SELECT "Namesake" FROM "table_21060" WHERE "Longitude" = '189.5W'