CREATE TABLE table_51963 ("Train No." CLOB, "Train Name" CLOB, "Origin" CLOB, "Destination" CLOB, "Frequency" CLOB)

What is the frequency of the Chennai Egmore Dibrugarh Express to Dibrugarh?
SELECT "Frequency" FROM table_51963 WHERE "Destination" = 'dibrugarh' AND "Train Name" = 'chennai egmore dibrugarh express'
SELECT "Frequency" FROM "table_51963" WHERE "Destination" = 'dibrugarh' AND "Train Name" = 'chennai egmore dibrugarh express'