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_47803 ( "Round" real, "Pick" real, "Overall" real, "Name" text, "Position" text, "College" text )

### Question ###
What is the total round when DB was the position, and the pick less than 21, and Jeff Welch as the name?

### Accurate SQL ###

SELECT SUM("Round") FROM table_47803 WHERE "Position" = 'db' AND "Name" = 'jeff welch' AND "Pick" < '21'