CREATE TABLE table_204_851 (id NUMBER, "serial number" NUMBER, "river" CLOB, "name" CLOB, "area  ( km2 ) " NUMBER, "district" CLOB, "co-ordinate" CLOB, "altitude  ( m ) " NUMBER)

what is the name of the only reservoir in the kannur district ?
SELECT "river" FROM table_204_851 WHERE "district" = 'kannur'
SELECT "river" FROM "table_204_851" WHERE "district" = 'kannur'