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_26049 ( "Years led" text, "Span of years led" real, "Player" text, "Titles won at point of lead" real, "Total Career titles" real, "Tournament at which lead began" text )

### Question ###
At what tournament did pete sampras begin his lead?

### Accurate SQL ###

SELECT "Tournament at which lead began" FROM table_26049 WHERE "Player" = 'Pete Sampras'