MySQL 8.0

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

create table ta as (
select 1  pokedex_num, 'BULBASAUR' pokemon_name, 'BULBASAUR' evolution_line, 1 evolution_line_number union all
select 2  pokedex_num, 'IVYSAUR' pokemon_name, 'BULBASAUR' evolution_line, 2 evolution_line_number union all
select 3  pokedex_num, 'VENUSAUR' pokemon_name, 'BULBASAUR' evolution_line, 3 evolution_line_number union all
select 4  pokedex_num, 'SQUIRTLE' pokemon_name, 'SQUIRTLE' evolution_line, 1 evolution_line_number union all
select 5  pokedex_num, 'WARTORTLE' pokemon_name, 'SQUIRTLE' evolution_line, 2 evolution_line_number union all
select 6  pokedex_num, 'BLASTOISE' pokemon_name, 'SQUIRTLE' evolution_line, 3 evolution_line_number 
  )

Records: 6  Duplicates: 0  Warnings: 0


select * from ta


pokedex_num
pokemon_name
evolution_line
evolution_line_number


1
BULBASAUR
BULBASAUR
1

2
IVYSAUR
BULBASAUR
2

3
VENUSAUR
BULBASAUR
3

4
SQUIRTLE
SQUIRTLE
1

5
WARTORTLE
SQUIRTLE
2

6
BLASTOISE
SQUIRTLE
3


select t1.pokedex_num, t1.pokemon_name l1, t2.pokemon_name l2, t3.pokemon_name l3 from ta t1
left join ta t2 on t2.evolution_line = t1.evolution_line and t2.evolution_line_number = 2
left join ta t3 on t3.evolution_line = t1.evolution_line and t3.evolution_line_number = 3
where t1.evolution_line_number = 1
Order by t1.pokedex_num


pokedex_num
l1
l2
l3


1
BULBASAUR
IVYSAUR
VENUSAUR

4
SQUIRTLE
WARTORTLE
BLASTOISE

pokedex_num	pokemon_name	evolution_line	evolution_line_number
1	BULBASAUR	BULBASAUR	1
2	IVYSAUR	BULBASAUR	2
3	VENUSAUR	BULBASAUR	3
4	SQUIRTLE	SQUIRTLE	1
5	WARTORTLE	SQUIRTLE	2
6	BLASTOISE	SQUIRTLE	3