CREATE TABLE table_50138 ("Name" CLOB, "Latitude" CLOB, "Longitude" CLOB, "Diameter  ( km ) " FLOAT, "Year named" FLOAT, "Name origin" CLOB)

COunt the average Diameter (km) which has ketian (yenisey r.) main evil goddess.?
SELECT AVG("Diameter (km)") FROM table_50138 WHERE "Name origin" = 'ketian (yenisey r.) main evil goddess.'
SELECT AVG("Diameter (km)") FROM "table_50138" WHERE "Name origin" = 'ketian (yenisey r.) main evil goddess.'