Table: bulgaria_fed_cup_players
Columns: player
w_l_total
w_l_singles
w_l_doubles
ties
debut
years_played

Question: what is the debut when the play er is radoslava topalova and the years played is less than 2?
SQL: SELECT AVG("debut") FROM bulgaria_fed_cup_players WHERE "player" = 'radoslava topalova' AND "years_played" < 2