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_9819 ( "Rider" text, "Bike" text, "Laps" real, "Time" text, "Grid" real )

### Question ###
What is the sum of the laps with a grid less than 28, retirement time, and a ducati 1098 f08 bikes?

### Accurate SQL ###

SELECT SUM("Laps") FROM table_9819 WHERE "Grid" < '28' AND "Time" = 'retirement' AND "Bike" = 'ducati 1098 f08'