Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_53157 ( "Year" real, "Winners" text, "Grand Finalist" text, "Scores" text, "Venue" text, "Crowd" real, "Margin" real, "Season Result" text )

### Question ###
What grand finalist had a year after 1979, a margin smaller than 30, and winners of essendon?

### Accurate SQL ###

SELECT "Grand Finalist" FROM table_53157 WHERE "Year" > '1979' AND "Margin" < '30' AND "Winners" = 'essendon'