Table: tennis_match_stats_6
Columns: edition
round
date
against
surface
opponent
result

Question: Who was the opponent for the 2003 davis cup europe/africa group ii?
SQL: SELECT "opponent" FROM tennis_match_stats_6 WHERE "edition" = '2003 davis cup europe/africa group ii'

Question: What is the round when the match was against sergis kyratzis?
SQL: SELECT "round" FROM tennis_match_stats_6 WHERE "opponent" = 'sergis kyratzis'