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_77573 ( "Position" real, "Club" text, "Played" real, "Points" text, "Wins" real, "Draws" real, "Losses" real, "Goals for" real, "Goals against" real, "Goal Difference" real )

### Question ###
What is the average goal difference with 51 goals scored against and less than 17 losses?

### Accurate SQL ###

SELECT AVG("Goal Difference") FROM table_77573 WHERE "Goals against" = '51' AND "Losses" < '17'