Table: georgios_reppas_athlete_data
Columns: name
pos
height
weight
date_of_birth
club

Question: What is the weight of the player from club panionios g.c. and was born on 1975-05-21?
SQL: SELECT "weight" FROM georgios_reppas_athlete_data WHERE "club" = 'panionios g.c.' AND "date_of_birth" = '1975-05-21'